Electric-field switching magnetization and spin transfer in ultrathin BiFeO3 film

TL;DR

This study demonstrates that applying an external electric field to ultrathin BiFeO3 films can switch their magnetization by 90 degrees, revealing potential for electric control of spintronic devices.

Contribution

It introduces a first-principles approach showing electric-field-induced magnetization switching and orbital-driven spin transfer in ultrathin BiFeO3 films, advancing multiferroic spintronics.

Findings

Electric-field induces 90-degree magnetization switching.

Surface spin polarization depends on field direction.

Fe-t2g orbital reconstruction drives exchange bias.

Abstract

First-principles density-functional theory calculations show switching magnetization by 90 degree can be achieved in ultrathin BFO film by applying external electric-field. Up-spin carriers appear to the surface with positive field while down-spin ones to the negative field surface, arising from the redistribution of Fe-t2g orbital. The half-metallic behavior of Fe-3d states in the surface of R phase film makes it a promising candidate for AFM/FM bilayer heterostructure possessing electric-field tunable FM magnetization reversal and opens a new way towards designing spintronic multiferroics. The interface exchange-bias effect in this BFO/FM bilayer is mainly driven by the Fe-t2g orbital reconstruction, as well as spin transferring and rearrangement.